Motor/Sailing Vessels, (MotorSailer), Catamaran

Discussion in 'Boat Design' started by brian eiland, Mar 15, 2007.

  1. MikeJohns
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    MikeJohns Senior Member

    High labor input is cheap in SE Asia if you shop around and skill levels are high.

    As for power, that's where you need professional input.

    Here's a HP requirement vs Froude number graph for a 35 ton 56' LOD, 47' LWL motorsailor, in smooth water, this is an easily driven hull that also sails well .

    Add 40% for motoring into boisterous weather offshore. A Fn of around 0.35 is the more sensible design point for long distance cruising under power.

    If you require faster speeds at times that's perfectly achievable but really requires a variable pitch prop setup.
     

    Attached Files:

  2. FAST FRED
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    FAST FRED Senior Member

    Interiors are usually expensive to construct , but with the use of modern water cut plywood the entire unit could be pre cut , pre finished , varnished for the dark coffin interior lovers or painted .

    The hull creator would slide together the pre cut pieces and drop them into the hull before the deck is placed on.

    Lots of computer work , but by choosing the interior plan different requirements could be met at low cost.

    IF the hull plans was open to all , low cost designers could create a special interior , and the custom cut/finished ply would remain about the same cost.

    Any more ideas out there to bring back the $1,000 a foot cruising boat?

    Another big saving could be the use of Re Man engines and trannys.

    These when factory done have a guarentee similar to a new and are fine in use.

    John Deere (farm engines) have a few sales per year that do not require an exchange engine , some Twin Disc dealers are similar.
     
  3. ElGringo
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    ElGringo Senior Member

    Fred, I am very, very, Un-Aware of most things in boating, but for sure I did not know of the "Hull Companies" who are they and where are they?
     
  4. Angélique
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    Angélique aka Angel (only by name)

  5. Squidly-Diddly
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    Squidly-Diddly Senior Member

    make it a Convertible with raise-able pilot house structure, similar to older MacGregors.
     
  6. FAST FRED
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    Today the old 50/50 MS concept is long obsolete.

    Most cruising sail boats today are really 90/90's.

    Compared to a "pure" 100% sail boat the engine , tanks ,prop and required extras probably reduce the boats efficiency by 10%.

    The weight of the sailing rig and required ballast would also reduce the efficiency of a "pure" motor vessel, although modest ballast is carried on some offshore motor boats.

    So we already have a modern MS in most cruising boats , although the hulls could be made to carry more weight if long fuel range is required.

    A look in Pro Boat Builder magazine will reveal a number of hull builders , many in the NE of the USA.

    Wiring , for the initial build , and for the usual changes over the next few decades would be handled with a trough the wires are simply laid in.

    Not hard to do in the initial interior design , and a blessing for every owner in the future.
     
  7. ElGringo
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    ElGringo Senior Member

    I found the Pro Boat magazine but did not find anyone in the classified section selling just the hulls. I did find that Blue Planet Catamarans is for sale for 300K. That's a nice little cat but in my opinion he tried to build too much into it and it got way over priced. Two heads, two showers and sleeps six in a 32 foot cat? However a bare boat would be just about the perfect starting place. I don't even like fancy wood, too much work.
     
  8. brian eiland
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    brian eiland Senior Member

    2 particular Monohull Motorsailer Designs & Cost to Build

    I realize I utilized the word catamaran in the title of this subject thread, and that was because I was touting the catamaran hull form as a superior one for a motorsailer that could perform better in both the power and sailing modes.

    But not all boaters accept the multihull 'philosophy', and those folks want to stick with their monohull history/philosophy. Even myself as a confirmed multihuller can appreciate some monohull designs, and I am particularly fond of these two 'old designs',...both from an appearance and a multi-functionality point of view.

    I actually believe they might have some marketability in the future (albeit in limited numbers), particularly if they offered a long term cruiseability/liveaboard alternate for an older couple, and a price that might allow that purchase.

    And I think when the fuel prices start on their upward march again, there may be some powerboaters that could be attracted to such a vessel design(s). But those folks require stand up head room through out, nice big saloons, big heads, big galleys, big windows, protected cockpits, and even flybridges.

    These 2 designs being monohulls offered the possibility of steel construction, ....at least of the hull portion. In the back of my mine was the security I would feel when I sailed off to those Pacific islands and other far out locations often protected by many surrounding reefs, or running down a wayward container floating haphazardly in the ocean. Wouldn't that older couple desire that security of a steel hull also!

    And couldn't that steel hull be built at a reasonable cost, and particularly in a limited production scheme.

     
  9. brian eiland
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    brian eiland Senior Member

  10. brian eiland
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    brian eiland Senior Member

    So lets start with the steel hull portion. I have suggested a 'frameless' hull construction,.... subcontracted out. This South African fellow did a bit of steel hull boat building, and prevously posted a lot of discussions over on Boatdesign.net. He has now retired from boatbuilding, but he has left a website up.
    Final painting & delivery | Steel Boatbuilding

    Here is some portions of his frameless discussion:
    Building Upright or Upside Down | Steel Boatbuilding

    Plating a Multi Chine Hull | Steel Boatbuilding
    ...look down the page
    THE V/D STADT FRAMELESS CONSTRUCTION METHOD


    COMPLETE BUILT - DIX 43 | Steel Boatbuilding
    six guys in his crew including himself

    If we doubled that build time of his for the 'frameless hull method', it would still make financial sense, wouldn't it? ...and notice that his 3 wk figure includes the deck which he claims is a real time consumer.

    I would be hoping NOT to use a steel deck,...for a number of reasons, including big weight addition, and future maintenance issues.


    This was one of his early postings that got my attention,...look down to WynandN
    Frameless Construction - Page 2 - Boat Design Forums
    ...18 working days to build the 34' hull and deck (and I think he did his own panel cutting by hand rather than computer cut)
     
  11. brian eiland
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    brian eiland Senior Member

    CNC-cut Metal Kits, ProBoat Magazine Article

    There is an interesting affirmation article concerning CNC-cut metal kits in the latest issue #148 (Apr/May 2014) of Professional Boatbuilder:
    Table of Contents, Professional BoatBuilder Magazine

    Precisely engineered CNC-cut metal kits simplify custom and production projects at aluminum sailing-yacht builder K&M and steel-motoryacht builder Jetten, ..both in the Netherlands


    In case you are unable to access this article on-line, I will just hi-lite a few of the notable observations:
     
  12. brian eiland
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    brian eiland Senior Member

    Liveaboard Cruisier for the Real World

    Just ran across this old posting on another 'motorsailing' subject thread.

     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    Im not sure what it is you're trying to suggest with this posting?

    CNC parts have been used for decades. We started using them in the early 90s. Only small yards/home build has not utlised this method - that's all.

    As for saving time - again a myth. Where does the cut part come from..er...a set of cutting files...where does this come from...er...a set of CAD files...where do these CAD files come from...a set of CAD structure dwgs. It takes time, a lot of time, to draw up and extract every single cutting part and identifying the best location to split the frames for maximising cutting and minimising waste and labour time in construction etc. What you don't see in 'time' on the shopfloor, you see heaps of additional time in the DO to produce said cutting files.
     
  14. brian eiland
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    brian eiland Senior Member

    Agreed,... there is a lot of time creating those initial files, but then you don't need repeat that time to the 'building time' of subsequent boats.

    Perhaps we could term it 'tooling time', but I'll bet in these days that file creation tooling time could be a lot less than the actual time to build molds etc (tooling) for a production run of vessels.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    How many home builds do repeats?...and very few commercial yards do repeats, with zero changes. Great if you can, but exception rather than the rule. But it is also true for any repeat build whether using CNC parts or not - repeat builds take less time.

    Designing and building boats takes "time". The amount of time is merely moved from one "process" to another. In fact our experience shows attempting to do everything in the DO, rather than on the shopfloor leaves the guys on shopfloor with their brains switched off - more errors creep in as the "thinking" tends to go out the window when faced with endless ready made cut parts like a jigsaw. It is a CNC cut part - it must be right....so it is constructed whether right or wrong as it is not to be questioned - it is MADE by computer!!

    Those who constantly harp on about how great CNC and 3D modelling etc is, clearly have not worked in commercial shipyards to see where all the costs and implications of moving different procedures from one Dept to another go. There is no such thing as free lunch!
     
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